The present disclosure relates to a semiconductor device, and is applicable to an injection enhancement (IE)-type trench insulated gate bipolar transistor (IGBT).
A trench gate IGBT is widely used as an IGBT having a low collector to emitter saturation voltage VCE(sat), and the IE-type trench gate IGBT using the IE effect is developed to further promote conductivity modulation. Such an IE-type trench gate IGBT includes one IGBT having a structure, in which active cells actually coupled to an emitter electrode and inactive cells each having a floating P body region are alternately arranged in a cell region, thereby holes are easily stored on a main device surface side (emitter side) of a semiconductor substrate (for example, Japanese Unexamined Patent Application Publication Nos. 2012-256839 and 2013-140885). In this type of IE-type trench gate IGBT, an inactive cell region prevents holes injected from a collector side from escaping to an emitter side, thereby hole concentration increases between an active cell region and a collector side. Such increased hole concentration promotes electron injection from an emitter (source) side, so that electron concentration is also increased. Such increased carrier concentration (IE effect) causes conductivity modulation, allowing VCE(sat) to be reduced.